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UHPC Bridge Tech Helps to Transform “Dangerous Bridges” at Rural Roads in Eastern Guangdong, China


01Guangdong Provincial Highway Society (GPHS) was founded on July 16, 1976, and is an academic institution voluntarily formed by the highway & traffic authority, science and technology workers department and related fields in the province. This society is mainly focusing in the exchange of science and technology advancement, academic advisory services, project audit and evaluation, professional and technical training,talent recommendation, industry journal publishing and so on.



Guangdong Province is one of the major economic provinces for the entire China economy. Construction and development of highway and bridge started early thus results Guangdong Province become one of the top Province with large number of bridges built in China. After decades of these bridges constructed, most of these bridges now are in relatively bad shape and has categorized as “Dangerous Bridges” due to the services life limitation and the increasing traffic loading capacity to the bridge structures. In 2019, the project on the transformation of the dangerous bridges on the rural highway in Guangdong Province was included in one of the "Ten People's Livelihood Facts" project of the Guangdong Provincial Government, and tender and construction process of the said bridges was officially launched in January 2019.

On March 14, 2019, Guangdong Construction Engineering Group Co., Ltd. (GCEG) and Guangdong Transportation Group Co., Ltd. (GTG) built a general contracting consortium, winning the bid for the I. and II bid stakes, respectively. GCEG on March 29 and the Guangdong Provincial Highway Affairs Center (GPHAC) has signed a general contracting agreement (refer to Figure 1), according to the general contracting agreement, the construction group is responsible for the construction of seven cities in eastern Guangdong Shantou, Chaozhou, Meizhou, about 140 dangerous bridges needed to be strengthened or rehabilitate, the winning bid amount is RMB 219 million yuan.




On July 20, 2019, the second meeting on the review of the repair/rehabilitation and new bridge construction drawing for the general contracting of the Ⅰwas organized in Guangzhou. Construction drawings for reinforced and newly constructed bridge of 34 bridges are under reviews including the JingLi Bridge and Xidong Bridge. During the meeting, the design institute and construction contractor conducted in-depth research and discussion on the use of the precast/prestressed UHPC composite bridge concept. Finally, ZhungLu Dura International Engineering Co., Ltd. (ZDIE) was selected as the UHPC products supplier. The Liji Bridge, Wucun Bridge, and Xiapujingkou Bridge were used as pre-reconstruction tasks. The design adopted 100 pieces of 15-meter, 16-meter, and 20-meter I-type UHPC composite beams. ZDIE is dedicated to research and development, specializing in UHPC materials research and development production, structural research and development design, equipment research and development equipment, project implementation and other industrial chain solutions. With the advantages of UHPC's extraordinary durability, superior corrosion resistance, improved aesthetical appearance and meeting the conditions of rapid prefabrication, it meet the key points and essential needs of the old bridge reconstruction of rural highways.

The JingLi Bridge is located on the X096 line in Jiexi County, Jieyang City, which leads from north to south. The whole bridge is divided into left and right lanes. The superstructure was made from ordinary reinforced concrete T-beam and the substructure is ordinary RCC column and piers. The left and right panels have different load history due to there were constructed at different years. The two bridges are referred as the new bridge on the left lane and old bridge on the right lane. Taking the Jiexi direction as the small station and the Puning direction as the large station, the left bridge consists of 8 spans × 16m + 3 spans × 20m + 4 spans × 16m long; whereas the right bridge consists of 8 spans × 16m + 3 spans × 20m + 8 spans × 16m long. The width of each bridge deck is 8m. The deck pavement is cement concrete pavement. The substructures are twin circular RCC columns connected with bored pile foundation. The construction of the new bridge on the left was started in 1997 and opened to traffic in 1998. The design load rating is car-20 and hang-100. In 2019 JingLi Bridge has been inspected for it health and fitness, and it has come to know that the original bridge surface is partially damaged and part of the upper structure was seriously damaged. The left lane bridge has now been closed and only the right lane bridge is in service (see Figure 4).

In view of the actual situation of the bridge, the design unit decided to replace the original RCC beam with the UHPC precast/prestressed I-beam which are manufactured by Zhunglu Dura International Engineering Co., Ltd. Two comparison schemes were studied during the value engineering scheme:

Scenario comparison table

 

Scenario 1:

Scenario 2:

Comparing projects

Using RCC T-shaped beams according to the 2018 specification

Using I-shaped UHPC precast beam according to the 2018 specification

Constant load conditions

21% increase of self-weight on the original structure

5% increase of self-weight on the original structure

Construction

Single-piece of T beam weight 30.6 tons, scaffolding needed, long construction cycle, high cost of temporary measures, large impact on traffic

Single-piece I beam weight 7.3 tons, no temporary work is needed, the whole bridge can be installed with small size automobile cranes, the construction cycle is short, minimum impact on traffic

Maintenance

Conventional concrete structure, easy to crack, steel corrosion, long-term maintenance

No cracking, full-life cycle without maintenance

Economics

RMB1954/m2 (upper structure only)

RMB1950/m2 (upper structure only)

JingLi Bridge is among the largest bridge and hardest to build. Based on various unfavorable factors, the experts and leaders has chosen ZhungLu Dura International Engineering Co., Ltd. I-shaped UHPC composite bridge in the reconstruction program. During the construction, the existing superstructure were demolished and replaced with UHPC precast beam and later cast with in-situ NC deck. The substructure and foundation are remained unchanged. 20-meter I-beams and 16-meter I-beams are used. The 20m long UHPC beams are 19.92 meters long to be exact, 0.7 meters high, 0.4 meters wide, and weight 7.3 tons; the 16m long UHPC beams are 15.92 meters long to be exact, 0.62 meters high, 0.4 meters wide, and weight 5.9 tons. After the construction of the UHPC composite bridge, the dead load of the superstructure was reduced by about 35%. The bridge foundation was a pile foundation, which greatly improved the bridge's anti-overload capacity.

During the review meeting, the following advantages has been realized by using UHPC tech:
  1. Compared with conventional concrete structures, the new superstructure weight can be reduced by 40%-60%,
  2. The construction cost of the UHPC composite bridge is competitive as compare to conventional design,
  3. UHPC beam is user friendly such as construction costs such as transportation and installation are greatly reduced,
  4. Shorter construction period and thus minimized traffic impact,
  5. UHPC has super durability, maintenance-free throughout the life cycle, simple and convenient management.
Finally, three bridges of Xidong Bridge (溪东桥), JingLi Bridge (金鲤大桥) and Xiapujingkou Bridge (下铺径口桥) were selected as the first-stage pilot projects with the aim to introduce this advanced UHPC bridge tech into China. The applications of each bridge are as follows: 1. Xidong Bridge: 3-spans Type-I UHPC composite beam with a span of 16m; 2. JingLi Bridge: 3-spans I-type UHPC composite beam, with first span of 16m and remaining two spans of 20m. 3. Xiapujingkou Bridge: 2-spans Type-I UHPC composite beam, with two spans of 15m, and two spans of 12m.

With the effective control of the domestic Covid-19 epidemic, the ZhungLu-Dura now has resumed work in the East Guangdong dangerous bridge transformation project. Contractor will make full swing to complete construction with quality assurance and completed in accordance with the general contracting unit provisions and duration, to build more convenient travel "safety bridge” and "well-off bridge." for the people of eastern Guangdong.

Link: https://mp.weixin.qq.com/s/5EEpkuqgTzWNbhatd_0Zvw

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